Assemblies for filtering particles and regenerating by post-combustion on a catalyst comprise, on the one hand, a particle filter and, on the other hand, a post-combustion catalyst, those two elements being located in a single metal casing having an upstream inlet opening for receiving the gases coming from the engine and a downstream opening for discharging the gases after filtration and regeneration by post-combustion. In general, the particle filter is placed downstream of the post-combustion catalyst in the casing, so that the gases coming from the engine first pass through the post-combustion catalyst before arriving at the particle filter.
After some time in use, it is necessary to clean the particle filter of the combustion residues, especially the residues of fuel additives, which accumulate on the filter. This cleaning operation is carried out especially by spraying water and air, which enables the residues to be detached and dissolved. If this cleaning operation is carried out in the casing assembly comprising the post-combustion catalyst and the particle filter, there is a risk that the post-combustion catalyst will be damaged. Furthermore, the cleaning quality is not optimum.
In order to avoid damage to the post-combustion catalyst and in order to clean the particle filter only, it is known to manufacture the casing in two successive portions, the one containing the particle filter and the other the post-combustion catalyst, the two portions being assembled one on each side of a separation plane by assembly means, such as a system of flanges welded to the surface of each of the two portions of the casing. It is thus possible to separate the two portions in order to clean the portion containing the particle filter.
Since it is absolutely necessary to maintain complete sealing at the site of the separation, it is necessary to use solid flanges clamping between them a seal placed between the flanges. The securing of the flanges necessitates the use of a large number of screws with nuts, all of which measures increase the cost and the radial space requirement of the assembly.
The present invention proposes to overcome those disadvantages.